Free piston engine



Oct. 21, 1941. F, JOHN ET AL 2,260,252

FREE PISTON ENGINE Filed Jan. 9, 1941 3 Sheets-Sheet 1 n l u l n n n 4 n 5 I lllIll/lllllllllll/llIIll/l/LVIIlllll/lIl/l/I Mw /n//en 0(5' A @www Oct. 21, 1941.. F JOHN ETAL 2,260,252

FREE PISTON' ENGINE Filed Jan. 9, 1941 's sheets-sheet 2 f 57 A .f6 26 Oct. 21, 14941. F, JOHN ETAL 2,260,252

FREE PISTON ENGINE Fiied Jan. 9, 1941 s sheets-sheet 5 Patented Oct. 21, 1941 FREE rIsroN ENGINE Fritz John and Adolf Steinbecher, Munich- Allach, Germany, assignors to the firm Forschungsanstalt Prof. Junkers Gesellschaft mit beschrnkter Haftung, Munich-Allach, Germany Application January 9, 1941, Serial No. 373,776 In Germany January 6, 1940 7 claims (c1. 23o-s6) 'Ihis invention relates to improvements in freeflying piston engines the flying mass of which is connected, over a gear transforming rotary into reciprocating motion, with a shaft to which a hand crank or other lever may be attached by means of which the shaft may be turned and the flying mass brought into starting position,l whereupon the engine can be set in :motion by admitting compressed air or other gas.

Engines of such construction hitherto involved dangers when the operator overlooked to remove the hand crank or the like from the shaft before the starting gas was allowed to enter the engine, because in this case the hand crank by swinging rapidly to and fro could cause accidents.

The object oi' the invention is to prevent such accidents. For this purpose a blocking device is provided which allows the admission of the compressed gas to the machine only after the hand crank or other lever has been removed from the machine.

According to the invention, in the compressed gas pipe leading to the free-#dying piston engine or in a branch-pipe connecting the pressure pipe with the open air a shut-ofi.' member is arranged with which a member (blocking member) is rigidly or otherwise connected in such a manner that in the one position of the shut-off member in which the admission of compressed gas to the starting chamber of the machine is prevented, the blocking member is situated in such a manner that putting-on the hand crank or the like is possible, but in the other position of the shut-off member in which the starting chamber can be filled with the compressed gas the blocking member projects into the space which is occupied by the hand crank or the like when put on the shaft, so that the shut-oil' member can be brought into this position only when the hand crank or the like is removed from the shaft.

When the shut-oil. member is arranged in the compressed gas line itself, the arrangement must y oil' device provided in the compressed gas line,

be such that this member can only be opened when the hand crank is removed from the shaft, but it must be closed at all times when the hand crank is put on the shaft.

When the shut-off member is provided in a branch-pipe leading from the compressed gas line to the open air, it must be opened when the hand crank is put on the shaft so that when in this case compressed gas is by mistake admitted to the starting line, this compressed gas can flow over the open shut-01T member to the open air, and is thus prevented from setting the engine in which member has the form of a slide and is displaceable by means of a hand crank;

Fig. 3 shows, in longitudinal cross-section, a /alve likewise arranged in the compressed gas Fig. 4 is a detail view, partly in cross-section, of the blocking member. and the hand crank belonging to Fig. 3; y

Fig. 5 shows, in longitudinal cross-section, a

valve disposed in apipe branching from the compressed gas line;

Figs. 6 and 7 show, respectively, a front-view and longitudinal cross-section on the line VII-VII (Fig. 6) of a valve likewise disposed in a pipe branching from the compressed gas line.

Referring first to Fig. 1, I is the casing of a free-flying piston engine comprising an internal combustion cylinder 2 coaxially connected at both ends with two compression cylinders 3 and 4. In these cylinders two flying masses each of them consisting of motor pistons 5, 1 andcompressor pistons 6, 8 are reciprocated in opposite directions. The flying masses 5', 6 and .'I, 8 are connected with each other by a coupling gear in such a manner that they are forced to make corresponding opposite motions. In the example shown a rack and pinion gear'is used for coupling, the masses 5, 6 being connected with the rack` 9, and the masses 1, 8 with the rack IU. The teeth of these racks engage at diametrically opposed points the teeth of la cog-wheel I2 Xed on a shaft I I journaled in the casing I of the engine. Thish shaft at its free end carries a square I3 on which a hand crank or other lever may be put.

For starting the yfree-flying piston engine the ilying masses must be brought into or nearly into a dead position, for instance, into the outer dead position as regards the motor cylinder. This is effected by turning the hand crank mounted on the shaft II in the corresponding direction.

motion. It should be possible to close this shut- 53' After the flying masses have been brought into startingy position, the'y are to the action the latter, for instance, into the compression chambers 3, 4. Hereby the flying masses are projected towards each other. The explosive charge which in the meantime was introducedy into the combustion cylinder 2 is hereby compressed between the motor pistons l, 1 and then ignited, so thatthe'- resulting vcombustion gases again drive asunder 4the ilying masses. The engine is nowset in motion and does its work o'f compressed gas (for instance, air) by admitting other. A y In the modification-shown in Figs. 3 and 4' a valve 48 isarranged in a housing 50 and pipes c l I l n I' full lines in Fig. 2 in which position the orifices of the pipes I9 and 29 communicate with each I9, 28' lead from the source of compressedgas over this-valvev tothe engine as shown by dotted arrows. The ,body of/this valve is normally held pressed -onto its seaty 5I by a spring' 49. Thel valve maybe opened by a two-armed lever 51 swinging about a stationary lfulcrum 56. One

(compressing air' in the vcompression cylinders 3, 4) in the well-known manner.

Now if the operator when startingthe engine' had overlooked to remove the hand crank from the shaft'II before the startin gas was admittedto the engine, the crank wo d take part inthe rapid oscillation of the cogfwh'eel of the engine, so that persons present would be exposed to considerable danger. Moreoverv it might happen f that the crank were pulled oE'from the shaft II and projected into thezroom. The possibility of suchy accidents is avoided by the devicesv described hereafter. Parts I9-, 2II,` 26, 21 are described in connection-with Fig. 2.

In the modification shown in Fig. 2 a slide :I6

movable in a casing I5 is inserted as a shut-off member'into the compressed gas line. Two pipes I9, 20 join at a distance withthe slide casing,

one ofwliich, I3 comes from the source of compressed Vgas 22 -and contains a,l shut-oil! member 2|, whereas the other pipe, 29, leads to the starting chambers of the free-flying piston engine,

4for instance 3, 4 (Fig. l) -The slide is provided with two pistons I1, I8 tightly 'adjoining theinner.wall of the casing and having a somewhat' greater distancefrom each other than-the oriilcesoi'.A pipes I9, 2Il.y vTherefore the compressed gas may` flow freely from pipe I9 to pipe 20, when the pistons and oriices are in a symmetrical relative position, as shown infull lines, but the ..An extension 36 outwardly projecting from the arm '60 of this lever serves asa blocking member vwhich is in such position with respect to the square I3, that the hand crank 26 can only be put on when the valve bodyv 46 is closed (position shownin full lines) and that the valve can only be- .opened when the hand crank is withdrawn A fromlthe square (position shown in dotted lines) For opening the valve 48 the lever 51 is swung in the direction of the arrow a until it egages.

on the abutment 58'.-` Hereby it -encounters.the valve stem and shifts it downwards together with the body 48. -As long as the hand crank is positioned on the square I3, the end of the arm 69 gets so near to the hub of the hand crank that it is impossible. to turn the lever 51 to open the valve46. Thereforejthe engine cannot be started as long as the 'hand crank is positioned, onthe square I3. e"

In the modification shown in Fig. l5, a valve is arranged in a pipe 33 branching from the compressed gas line 32v in such a manner that the valve body 34 opening towards the source of com- -v pressed gas is normally held pressedby a-spring 35 against its seat 31 'in the valve casing 36, thus I normally shutting oil the valve outlet leading to thel open air'. An extension 38 of the valve :stem projecting from the casingv 36 yserves as blocking member and is closely adjacent to the square I3 of the shaft II. When the valve is closed this member)y 38 is so near to the square I3 that it is impossible to put the hand crank 26 on the square I3. In thisposition the freeflying piston engine may be setin motion by .c

opening the shut-olf valve 2 I When it is desired to bring the ying massesr into starting position, at first the valve body 34 `must be brought into the open position against the action of the springv 35, inwhich posit-ion casing I6 operates, yas agblockingvmember, with f the collar, 21 on the hub; 'of the hand crank 26. i When the hand crank 28 is puton'the square I v I3 of the shaft II in order tube-able to bring the'ying masses 5, 6 and 1,18A (Fig. l) into 'their starting position, the collar 21 of` .thehand crank shifts the mttrmtothe position shown' by dotted lines in Fig'. 2, the piston I8 of the slide then takinga position betweewthefpipes I9 and 23 so as to separate the latter, If now by mistake the Putting the hand crank 26 on the square I3 is not prevented by member38..n For opening the valve `body 34 aha-nd lever 48 f swingabl'e about a stationary fulcrm 4I is used which withits one end engages a recess 42 of the blocking member 33 andat its otherfend o (the handle) carries la locking member consistlencounters the ,extension 3i)y of the slide I5 and valve 2I were opened and thereby 'gas `under pressure admitted fromthe source of compressed gas 22, the 4admission of compressed gas to pipe 20 and therewith ,tothestarting chambers of the engine would be prevented. This gas would rather escape into the open air through the annular slot v29 between the abutment 25 and the extension 30. 'Startingfthe engine vis therefore impossible as long as the hand crankl 26 is positioned on the shaft' II. The supply of conithe hand crank 26 is removed from the square I3. as only in this case the slide I5 can be brought, by the spring 24, into theposition shown with lpressed, gas to the engine is only possible when ingofan, auxiliaryy lever 43 and a link 44. Furthermore a shoulder or rest 39 is provided for the ,link 44 yin such a way that the link ywhen engaging this shoulderailxes the valve body 34 in its open position. lIn this open position ihe distance betweeny the member 38 and the square I3 is so great that the hand crank 26 can be put on the square." Nowif -byA mistake the valve in the compressed gas-line, were opened'to start the free-flyinglg-piston enginey this would be harmless, kas the compressed gas would be vable to escape into the open airfo/ver the open valve 34, 31 and, the outlet 45. In order .to be able ,to start the engine, at first the hand (crank must be removedvr again from the shaft II and,- then the valve 34, 31 must be closed.

The modification mustrated ,in Figs. s anda operates substantially. in the same v.manner as that*V shown in Fig.v 5 to'wit a valve, opening toto the open air. The valve body 8! is perma ncntly exposed to the action of a .spring S1 tending to close it. On the valve stem 64 projecting outwards from the valve casing I3 a knob or handle 85 is keyed carrying a swing arm 66 which acts as a blocking member. This arm is swingable about the axis of the valve and is axially displaceable together with the valve body I2. In the one position E of this arm (shown in Figs. 6 and 'I in full lines) the valve 6! is in shut-off position, and the end of arm 8B is so near to the square I3 of the shaft Il that the hand crank 28 cannot be put on the square I3. In this position of the arm BI the engine may be started. To bring the :dying masses of the engine into starting position, the valve body 82 is shifted into the open position by pressing the knob 85 against the force of the spring 61. Hereby a corner 'Il projecting from the hub of the handle 65 is made to register with a groove 'I3 in the valve casing 63. By turning the handle 85 in the sense of the arrow b (Fig. 6) the corner 'Il enters the groove 13 Vand engages the wall 12, whereby the valve body is secured in its open position. By this rotation the arm 66 has been brought into the position A shown in Fig. 6 in dotted lines in which position the hand crank 26 can be put on the shaft Il. Starting the engine is impossible in this case, because the compressed gas would escape into the open air through the opened valve and the orifice l5.

Also the shut-ofi' member positioned in the compressed gas line may be a slide-valve. In this case the arrangement-contrary to what is shown in Pig. 2-must be such that the passage is free when the flying masses of the engine are to be brought into the starting position, and

lthat the passage is shut off when the engine' is to be started.

We claim:

1. In a free-flying piston engine the combination of a shaft, a gear for transforming rotary into reciprocating motion connecting said shaft with the flying piston, a hand crank adapted to be put on said shaft and to bring the flying piston into a position adapted to start the engine by gas under pressure, a source of compressed gas, a pipe connecting said source with the 'engine, and a displaceable member releasing from pressure, in its one position. the pipe connected with the engine. and. in its other position,.effecting the blocking of the space for putting-on the hand crank.

2. In a free-flying piston engine the combination of a shaft, ay gear for transforming rotarv into reciprocating motion connecting said shaft with th'e flying. piston, a hand crank adapted to be put on said shaft and to bring the flying piston into a position adapted to start the engine by gas under pressure, a source of compressed gas, a pipe connecting said source with the engine. a shut-off member in said pipe, and a blocking member connected with the shutoff member in such a manner that the space for putting-on the hand crank is blocked when the shut-ofi.' member opens the passage for the compressed gas. and inversely this passage is shut off when the space for putting-on the hand crank is free.

'3. In a free-flying piston engine the combination of a shaft, a gear for transforming rotary into reciprocating motion connecting said shaft with the flying piston. a hand crank adapted to be put on said shaft and to brinsy the flying piston into a position adaptedto start the engine by gas under pressure, a source of compressed gas,

a pipe connecting said source with the engine,

a pipe branching from this pipe and leading .to the open air, a shut-off member in said branch pipe. and a blocking member connected with the shut-off member in such a manner that the spacel for putting-on the hand crank is free when the shut-off member opens .the outlet for the compressed gas, and inversely this outlet is shut off when the space for putting-on the hand crank is blocked.

4. In a free-flying piston engine the combination of a shaft, a gear for transforming rotary into reciprocating motion connecting said shaft with the flying piston, a hand crank adapted to be put on said shaft and to bring the iiying piston into a position adapted to start .the engine by gas under pressure, a source of compressed gas. a pipe connecting said source with the engine, a valve inserted into said pipe comprising a housing, a slide therein consisting of two pistons connected with each other by a stem of smaller diameter leaving a channel between the pistons adapted to connect the inlet with the outletof the pipe, an extension connected with one end .of the slide and projecting outwards from the housing into the space required for putting-on the hand crank, and a spring tending to press said extension outwards, one of the pistons closing the inlet of the compressed gas pipe in that position of the slide in which the extension is pushed inwards by the hand crank.

5. In a free-flying piston engine the combination of a shaft, a gear for transforming rotary into reciprocating motion connecting said shaft with the flying piston, a hand crank adapted to be put on said shaft and to bring the flying piston into a position adapted to start the engine by gas under pressure, a source of compressed gas, a pipe connecting said source with the engine, a housing inserted into'said pipe, a valve in the housing, a spring tending to close the valve towards the source of compressed gas, a hand-operated swing-arm adapted to open the valve in its one position and to block the' space for putting-on the hand crank in the closed position of the valve and to give this space free in the opened position of the valve, said swing-arm itself being blocked by the hand crank as long as the latter is in position.

6. In a free-flying piston engine the combination of a shaft, a gear for transforming rotary into reciprocating motion connecting said shaft with the flying piston, a hand crank adapted to be put on said shaft and to bring the flying piston into a position adapted to start the engine by gas under pressure, a source of compressed gas. a pipe connecting said source with the engine, a pipe branching from the first-named pipe, a housing connected with the branch-pipe, a valve in this housing closing against the main pipe, the space after the valve communicating with the open air, a spring tending to keep the valve closed, a recessed extension of the valve body extending through the wall of the housing, a

hand lever fulcrumed at a point of the housing i into reciprocating motion connecting said shaft with the ying piston, a hand crank adapted to be put on said shaftand t0 bring the ilying piston into a. position adapted to start the engine by gas under pressure, a 'source of compressed gas, a pipe connecting said source with the engine, a pipe branching from the mst-named pipe, a

housingconnected with the branch-pipe, a valve in this housing closing against the main pipe, the space after the valve communicating with the open air. a spring tending to keep the valve closed, an extension of the valve body extending `mrrz JOHN.

mou' s'rEmBEcHER. 

